Processing of gas streams, such as via mass or heat transfer from a process gas, is widely used in the chemical and power-production industries. For example, liquid-gas contactors are often used for purifying or removing constituents from process gas streams. One example of such a process is large scale flue gas desulfurization (FGD) that uses mass transfer between gas and liquid to absorb and neutralize SO2 present in a flue gas. These systems are effective because of a relatively high interfacial surface area that can be generated and the relatively rapid kinetics associated with the chemistry of reactions occurring at the liquid-gas interface.
Liquid-gas contactors also consume a large amount of water, as moisture is continually lost via evaporation to the process gas stream unless and until the exhaust gas becomes water-saturated. Furthermore, these systems can produce large volumes of waste water that require treatment and disposal to manage the accumulation of soluble contaminants that may be absorbed in the liquid.